Electrophotographic image forming apparatuses, such as copiers, printers, facsimile machines, plotters, or multifunction machines including at least two of these capabilities develop electrostatic latent images with toner.
For such image forming apparatuses, various methods of forming toner patterns are proposed aimed at, for example, image quality improvement. Further, JP-2000-305339-A proposes use of multiple identical color toners different in shade depending on the density of images to be output.
In electrophotographic image forming apparatuses, it is possible that toner scatters in other areas (i.e., background) than the positions to be developed with toner, thus reducing color stability, which is a phenomenon generally called scattering of toner or toner scattering. Scattering of toner can degrade image quality.
To alleviate adverse effects caused by toner scattering, image forming conditions may be changed in response to the degree of occurrence of toner scattering. However, changing image forming conditions in response to the degree of occurrence of toner scattering may degrade color stability. Therefore, it is preferable that adverse effects caused by scattering of toner are reduced using image processing. Additionally, simply using multiple identical color toners different in shade depending on the density of images may be insufficient to reduce adverse effects on image quality caused by scattering of toner.